US5821654A - Bearing support for cylindrical rotating shaft bearing - Google Patents

Bearing support for cylindrical rotating shaft bearing Download PDF

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Publication number
US5821654A
US5821654A US08/518,504 US51850495A US5821654A US 5821654 A US5821654 A US 5821654A US 51850495 A US51850495 A US 51850495A US 5821654 A US5821654 A US 5821654A
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US
United States
Prior art keywords
bearing
housing
rotating shaft
seating
integrated
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Fee Related
Application number
US08/518,504
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English (en)
Inventor
Suk Ha Woo
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Samsung Electro Mechanics Co Ltd
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Samsung Electro Mechanics Co Ltd
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Publication date
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Assigned to SAMSUNG ELECTRO-MECHANICS CO., LTD. reassignment SAMSUNG ELECTRO-MECHANICS CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: WOO, SUK HA
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    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
    • H—ELECTRICITY
    • H02—GENERATION; CONVERSION OR DISTRIBUTION OF ELECTRIC POWER
    • H02K—DYNAMO-ELECTRIC MACHINES
    • H02K5/00—Casings; Enclosures; Supports
    • H02K5/04—Casings or enclosures characterised by the shape, form or construction thereof
    • H02K5/16—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields
    • H02K5/173—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using bearings with rolling contact, e.g. ball bearings
    • H02K5/1735—Means for supporting bearings, e.g. insulating supports or means for fitting bearings in the bearing-shields using bearings with rolling contact, e.g. ball bearings radially supporting the rotary shaft at only one end of the rotor

Definitions

  • the present invention relates in general to a bearing support for a cylindrical rotating shaft bearing for preventing partial deformation of the stator housing due to difference in cooling time and shrinkage between thick and thin parts of the housing during formation by injection molding.
  • brushless motors are suitable for use as, for example, capstan motors of camera recorders or video tape recorders.
  • Each typical brushless motor is provided with a stator housing for receiving a rotating shaft therein.
  • Such a housing of the brushless motor may be produced through die casting which provides highly precise dimensions for the housing.
  • die casting is problematic because housing formed by this process is expensive.
  • the stator housing may be formed through injection molding.
  • injection molding has a problem in that the dimensions of a housing formed by this process are not sufficiently precise to install motor parts, such as bearings, in the housing.
  • stator housing formed by injection molding may be partially deformed due to differences in both cooling time and shrinkage between thick parts and thin parts of the housing when cooling the resin in the mold.
  • the injection molding for forming the stator housing may be processed very slowly. However, this causes a problem in that the injection molding time is inevitably lengthened and thereby deteriorates productivity of the stator housings.
  • FIGS. 1 to 3 there is shown a typical brushless motor which may be preferably used as a capstan motor of a camera recorder or video tape recorder.
  • a rotor case 10 of the brushless motor includes two magnets, that is, a main magnet 12 and a frequency generating magnet 14.
  • the two magnets 12 and 14 are provided on the inner and outer surfaces of the rotor case 10 respectively.
  • a rotating shaft 16 is fitted into the center of the rotor case 10 with a bush 18 interposed between the case 10 and the shaft 16.
  • a snap ring 26 Fitted over the upper portion of the rotating shaft 16 is a snap ring 26. This snap ring 26 is brought into contact with a washer 24 seated in a washer seat 22 provided in the stator housing 20.
  • the stator 28 of the above brushless motor includes a stator housing 20 which is fitted into the center of a circuit board 30 so that it partially projects upwardly.
  • the housing 20 projects out of the top of the circuit board 30, while the rotating shaft 16 extending in the stator housing 28 projects out of the top of the housing 20.
  • a drive coil 36 corresponding to the main magnet 12 is wound on a stator core 34.
  • a magnetic resistor 38 corresponding to the frequency generating magnet 14 is mounted on the bottom surface of the circuit board 30.
  • the integrated housing 20 has a center through hale 40.
  • the washer seat 22 is formed in the top end of the through hole 40.
  • FIG. 2 shows the housing 20 inverted from the state of FIG. 1.
  • the housing 20 also includes a plurality of outside through bolt holes 44 which are vertically formed about the center through hole 40.
  • the outside through holes 44 are circularly arranged in the housing 20 at regular intervals.
  • the drive coil 36 of the stator core 34 is applied with electric current (DC).
  • the rotor case 10 thus rotates due to the interaction between the rotating magnetic field formed by the drive coil 36 and the DC magnetic field formed by the main magnet 12 of the rotor case 10.
  • the rotating shaft 16 thus rotates.
  • the magnetic resisting device 38 senses the signals generated by the frequency generating magnet 14 of the rotor case 10 and thereby controls the rotating velocity of the motor to maintain a constant velocity of the motor.
  • top and bottom bearings 42 The rotating motion of the rotating shaft 16 in the housing 20 is supported by the top and bottom bearings 42.
  • the centers of top and bottom bearings 42 should be correctly aligned with each other.
  • the radial surface of each bearing 42 should be exactly perpendicular to the central axis of the rotating shaft 16. Because this is difficult to achieve with separable housings, an integrated housing, as shown, is preferred.
  • FIG. 2 shows the bearings 42 fitted in the housing 20.
  • the bearing seat steps 41 of the housing 20 may be deformed due to the difference of cooling time and of shrinkage between thick parts and thin parts of the housing 20 when cooling the melted resin during formation of the housing 20 by molding. Due to the above deformation of the bearing seat steps 41 of the housing 20, the bearings 42 may not be correctly seated in the housing 20. When the bearings 42 are not correctly seated in the housing 20 as described above, the rotating shaft 16 will eccentrically rotate in the housing 20. Such an eccentric rotation of the shaft 16 prevents smooth rotation of the motor and shortens the expected life span of the motor, thereby deteriorating the operational performance of the goods having the above brushless motor.
  • an object of the invention to provide a bearing support for a cylindrical rotating shaft bearing of brushless motor in which the above problems can be overcome and which is provided with holes formed in thick parts of a stator housing of the motor to thereby prevent shrinkage of the thick parts of the housing when forming the housing through injection molding, the holes being formed in the stator housing by appropriately positioning cores in the mold before injecting melted resin into the mold.
  • the present invention provides a brushless motor comprising a rotating shaft bearing and a housing for seating the bearing therein, further comprising: holes adapted for preventing a size deformation of the housing when forming the housing through injection molding, the holes being formed in a bearing seat mouth of the housing as well as in an outer portion of the mouth.
  • FIG. 1 is a sectional view of a typical brushless motor
  • FIG. 2 is a sectional view of a stator housing showing top and bottom metal bearings fitted in the housing;
  • FIG. 3 is a plan view of the stator housing of FIG. 2, showing the metal bearings fitted in the housing;
  • FIG. 4 is a sectional view of a stator housing of a brushless motor in accordance with a preferred embodiment of the present invention.
  • FIG. 5 is a sectional view of the stator housing taken along lines 5--5 of FIG. 4, showing weight reducing holes formed in the housing to prevent deformation of the housing due to shrinkage.
  • FIG. 6 is a sectional view of the stator housing, taken along lines 6--6 of FIG. 4.
  • FIGS. 4 through 6 show a brushless motor in accordance with a preferred embodiment of the present invention.
  • the housing 60 is formed through injection molding.
  • the center of the above housing 60 is provided with a penetrating hole 62.
  • a rotating shaft will be longitudinally received in the center of penetrating hole 62 in the same manner a described for the prior art brushless motor of FIG. 1.
  • Bearing seating steps 71 are mounted around the circumference of both mouths 70, 72 of penetrating hole 62 to receive the respective metal bearings 41.
  • At least one cavity 74 is formed in the top surface of the housing 60 between the upper portion of the center through hole 62 and the outside through holes 44. Additionally, a plurality of axial holes 78 are formed around the inner circumference 80 of the penetrating hole 62.
  • the arrangement of the cavities 76 and axial holes 78 formed in the housing 60 are best seen in the plan view of FIG. 5 while the arrangement of axial holes 78 are best seen in FIG. 6.
  • the cavities 76 and axial holes 78 may be formed by appropriately positioning cores in predetermined places in a mold before injecting melted resin into the mold.
  • the height of the cavities 76 be equal to or longer than the vertical height of a bearing 42.
  • the bearing seating steps formed in the housing 60 for seating the top and bottom bearings 42 the?rein can have correct size.
  • a plurality of ribs 82 are formed between cavities 76.
  • the number and thickness of the ribs 82 need not be deferred. Their width may be varied in conformity with the cavities 76 as long as the integrity of seating steps 41 is maintained so that bearings 42 can sufficiently support the rotating shaft.
  • an appropriate number of cavities 76 having a given height are formed in the stator housing 60 of the brushless motor. Due to the cavities 76, the amount of melted resin to be injected into the mold can be reduced and thereby substantially reduces the difference of cooling time between the thick and thin parts of he housing 60. Therefore, the housing 60 can be uniformly formed through the injection molding to prevent the deformation of the inside diameter of the housing 60 manufactured by means of molding.
  • the motor elements such as the metal bearings 42 can be precisely seated in the housing 60. Therefore, the brushless motor of this invention can achieve operational precision.
  • stator housing of this invention was formed within about 15 seconds which are substantially shorter than the prior art forming time, 50 seconds.
  • the present invention forms a precise stator housing of a brushless motor within a relatively short time. Therefore, the invention improves the assembling accuracy of the brushless motor and thereby remarkably improves the quality of the brushless motor.
  • the present invention not only saves processing time and raw materials of the housing, but also reduces the inferiority rate of the brushless motor. The invention thus cuts down the cost of the brushless motor.

Landscapes

  • Engineering & Computer Science (AREA)
  • Power Engineering (AREA)
  • Motor Or Generator Frames (AREA)
  • Brushless Motors (AREA)
US08/518,504 1994-08-23 1995-08-23 Bearing support for cylindrical rotating shaft bearing Expired - Fee Related US5821654A (en)

Applications Claiming Priority (2)

Application Number Priority Date Filing Date Title
KR2019940021230U KR0129508Y1 (ko) 1994-08-23 1994-08-23 브러쉬레스 모터용 하우징
KR199421230U 1994-08-23

Publications (1)

Publication Number Publication Date
US5821654A true US5821654A (en) 1998-10-13

Family

ID=19391254

Family Applications (1)

Application Number Title Priority Date Filing Date
US08/518,504 Expired - Fee Related US5821654A (en) 1994-08-23 1995-08-23 Bearing support for cylindrical rotating shaft bearing

Country Status (4)

Country Link
US (1) US5821654A (zh)
JP (1) JP2740140B2 (zh)
KR (1) KR0129508Y1 (zh)
CN (1) CN1042992C (zh)

Cited By (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6081058A (en) * 1995-06-07 2000-06-27 Minebea Co., Ltd. Motor structure having a permanent magnet motor with grooves to reduce torque ripples
US6144135A (en) * 1998-11-12 2000-11-07 Ho; Jsewen Stator structure for a direct-current fan motor
US6400052B1 (en) * 1999-04-02 2002-06-04 Seiko Instruments Inc. Motor and rotary apparatus having motor
US20030127552A1 (en) * 2002-01-09 2003-07-10 Tsukasa Shinmi Magnetic tape apparatus and method of manufacturing magnetic tape apparatus
US6700260B2 (en) * 2000-07-20 2004-03-02 Delta Electronics, Inc. Rotor structure of motor
US6735846B2 (en) 2001-01-09 2004-05-18 Black & Decker Inc. Method for forming an electric motor having armature coated with a thermally conductive plastic
US20060282902A1 (en) * 2005-06-10 2006-12-14 Hisashi Matsushita Security device and method for information processing apparatus
US20070024137A1 (en) * 2005-07-29 2007-02-01 Nidec Corporation Motor
US20070044312A1 (en) * 2005-08-29 2007-03-01 Matsushita Electric Industrial Co., Ltd. Bearing sleeve fixing mechanism, manufacturing method thereof and fan device having the same
US7685697B2 (en) 2001-01-09 2010-03-30 Black & Decker Inc. Method of manufacturing an electric motor of a power tool and of manufacturing the power tool
US7814641B2 (en) 2001-01-09 2010-10-19 Black & Decker Inc. Method of forming a power tool
US20120195776A1 (en) * 2009-07-18 2012-08-02 Ebm-Papst St. Georgen Gmbh & Co. Kg Fan comprising an electronically commutated drive motor
US8632254B2 (en) * 2012-04-30 2014-01-21 Honeywell International Inc. Bearing sump with bi-directional stiffness

Families Citing this family (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100362805B1 (ko) * 1999-10-25 2002-11-29 삼성광주전자 주식회사 세탁기용 모터의 하우징 조립구조
JP2004263821A (ja) * 2003-03-04 2004-09-24 Sony Corp 軸受装置及び回転駆動装置

Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2421592A (en) * 1944-11-16 1947-06-03 Gen Electric Dynamoelectric machine
US3483407A (en) * 1964-10-12 1969-12-09 Licentia Gmbh External and internal rotor electric motors with vibration dampers
US4117359A (en) * 1974-01-30 1978-09-26 Teldix Gmbh Bearing and drive structure for spinning turbine
GB1585337A (en) * 1977-04-28 1981-02-25 Mabuchi Motor Co Support
US4471250A (en) * 1982-10-21 1984-09-11 Emerson Electric Co. Hub assembly for dynamoelectric machine and method of making same
US4591276A (en) * 1984-01-14 1986-05-27 Skf Gmbh Radial ball-and-socket bearing
EP0633646A1 (de) * 1993-07-07 1995-01-11 EBM ELEKTROBAU MULFINGEN GmbH & Co. Lageranordnung für Elektro-Kleinmotoren
US5405199A (en) * 1991-12-03 1995-04-11 Mabuchi Motor Co., Ltd. Bearing device for miniature motors

Family Cites Families (1)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP2551350Y2 (ja) * 1989-04-13 1997-10-22 日本電産株式会社 スピンドルモータ

Patent Citations (8)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US2421592A (en) * 1944-11-16 1947-06-03 Gen Electric Dynamoelectric machine
US3483407A (en) * 1964-10-12 1969-12-09 Licentia Gmbh External and internal rotor electric motors with vibration dampers
US4117359A (en) * 1974-01-30 1978-09-26 Teldix Gmbh Bearing and drive structure for spinning turbine
GB1585337A (en) * 1977-04-28 1981-02-25 Mabuchi Motor Co Support
US4471250A (en) * 1982-10-21 1984-09-11 Emerson Electric Co. Hub assembly for dynamoelectric machine and method of making same
US4591276A (en) * 1984-01-14 1986-05-27 Skf Gmbh Radial ball-and-socket bearing
US5405199A (en) * 1991-12-03 1995-04-11 Mabuchi Motor Co., Ltd. Bearing device for miniature motors
EP0633646A1 (de) * 1993-07-07 1995-01-11 EBM ELEKTROBAU MULFINGEN GmbH & Co. Lageranordnung für Elektro-Kleinmotoren

Cited By (21)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US6081058A (en) * 1995-06-07 2000-06-27 Minebea Co., Ltd. Motor structure having a permanent magnet motor with grooves to reduce torque ripples
US6144135A (en) * 1998-11-12 2000-11-07 Ho; Jsewen Stator structure for a direct-current fan motor
US6400052B1 (en) * 1999-04-02 2002-06-04 Seiko Instruments Inc. Motor and rotary apparatus having motor
US6700260B2 (en) * 2000-07-20 2004-03-02 Delta Electronics, Inc. Rotor structure of motor
US7685697B2 (en) 2001-01-09 2010-03-30 Black & Decker Inc. Method of manufacturing an electric motor of a power tool and of manufacturing the power tool
US8324764B2 (en) 2001-01-09 2012-12-04 Black & Decker Inc. Method for forming a power tool
US8901787B2 (en) 2001-01-09 2014-12-02 Black & Decker Inc. Method of forming a power tool
US8850690B2 (en) 2001-01-09 2014-10-07 Black & Decker Inc. Method of forming a power tool
US8997332B2 (en) 2001-01-09 2015-04-07 Black & Decker Inc. Method of forming a power tool
US6735846B2 (en) 2001-01-09 2004-05-18 Black & Decker Inc. Method for forming an electric motor having armature coated with a thermally conductive plastic
US8937412B2 (en) 2001-01-09 2015-01-20 Black & Decker Inc. Method of forming a power tool
US7814641B2 (en) 2001-01-09 2010-10-19 Black & Decker Inc. Method of forming a power tool
US8203239B2 (en) 2001-01-09 2012-06-19 Black & Decker Inc. Method of forming a power tool
US9472989B2 (en) 2001-01-09 2016-10-18 Black & Decker Inc. Method of manufacturing a power tool with molded armature
US20030127552A1 (en) * 2002-01-09 2003-07-10 Tsukasa Shinmi Magnetic tape apparatus and method of manufacturing magnetic tape apparatus
US6956713B2 (en) * 2002-01-09 2005-10-18 Funai Electric Co., Ltd. Magnetic tape apparatus with capstan motor configuration
US20060282902A1 (en) * 2005-06-10 2006-12-14 Hisashi Matsushita Security device and method for information processing apparatus
US20070024137A1 (en) * 2005-07-29 2007-02-01 Nidec Corporation Motor
US20070044312A1 (en) * 2005-08-29 2007-03-01 Matsushita Electric Industrial Co., Ltd. Bearing sleeve fixing mechanism, manufacturing method thereof and fan device having the same
US20120195776A1 (en) * 2009-07-18 2012-08-02 Ebm-Papst St. Georgen Gmbh & Co. Kg Fan comprising an electronically commutated drive motor
US8632254B2 (en) * 2012-04-30 2014-01-21 Honeywell International Inc. Bearing sump with bi-directional stiffness

Also Published As

Publication number Publication date
JPH08182291A (ja) 1996-07-12
KR0129508Y1 (ko) 1998-12-15
KR960009382U (ko) 1996-03-16
JP2740140B2 (ja) 1998-04-15
CN1042992C (zh) 1999-04-14
CN1130820A (zh) 1996-09-11

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